Apparatus for treating ores.



jizmi/zafor Patented Sept. 25, I900.

C E f 1/. M44 AZDr/wy llw B G. M. WESTMAN.

(Application filed Dec. 16, 1899.)

IIIIIII Z APPARATUS FOR TREATING ORES.

(No Iodel.)

- UNITED STATES PATENT OFFICE.

GUSTAF M. WESTMAN, OF NEW YORK, N. Y., ASSIGNOR TO THE ARSENIOAL GOLD REDUCTION COMPANY, OF NEWARK, NEW JERSEY.

APPARATUS FOR TREATING ORES.

SPECIFICATION forming part of Letters Patent No. 658,536, dated September 25, 1900.

Application filed December 16, 1899. Serial No. 740,517. (No model.)

T aZZ whom it may concern.- 77, of wrought-iron, as shown in Fig. 2, and Be it known that I, GUSTAF M. WESTMAN, casting the iron electrodes about the pipes, so a subject of the King of Sweden and Norway, that the pipes are embedded within the castand a resident of New York, in the county of iron portions. Suitable means, as indicated 5 New York and State of New York, have inat K, are employed for furnishing electrical vented certain new and useful Improvements connection with the electrodes. The pipes are in Apparatus for the Treatment of Ores, of connected with a hydrant or reservoir S for which the following is a specification. supplying water to pass through the elec- My invention relates to the class of appatrodes, and thus keep them cool. The elec- 6o :0 ratus employed in the reduction of ores, the trodes I'I and H are usually placedin depres object being to provide a practicable and sions (1 01 The confronting upper surfaces economical apparatus for treating, more parmay be curved, as shown, in approximately ticularly, arsenic or similar ores and collectthe form of sections of parabolas to expose ing the arsenic and at the same time saving considerable superficial area to the ore, and 15 any precious metals or other valuable bithus secure good electrical contact therewith.

products which may be contained in the ores They are respectively connected with the teroperated upon. minals of any suitable source of electricity,

The treatment of arsenic ores in considerand for reasons hereinafter pointed out I usuable quantities has usually been found exally prefer to use alternating electric currents. 2o tremely diflicult and dangerous, owing to the In the drawings I have represented an alterpoisonous qualities of the arsenic-vapors, and nating-current generator H the terminals of any usual process of treatmentinvolves heatwhich are connected by conductors 1 and 2 ing in more or less open furnaces, and much with the terminals of the primary coil p of a of the arsenic-vapor is then liable to escape converter T. The secondary coil 5 has one 25 into the air. Such processes can therefore of its terminals connected with the electrode be carried on usually only in uninhabited H,while the remaining terminal is connected districts. By my invention the freeing of with the electrode H. A suitable regulatthe arsenic from the ore is accomplished in ing device R for adjusting the current may a closed chamber, from which the vapors be included in the secondary circuit of the So 0 are led off and gathered in a suitable contransformer or converter T. The coils of the densing chamber or vessel. At the same transformer are so proportioned with refertime the precious metals, which are usually ence to the electromotive force of the generpresent in more or less abundance, may be ator as to deliver currents of the required collected and saved. The heating and meltelectroinotive force and quantity to the fur- 5 ing is accomplished by means of electric ournace. It is not always essential that alterrents. nating electric currents be employed but they In the accompanying drawings, Figure l is possess the advantages of ready production a vertical section of a furnace or apparatus and convenient control and freedom from for carrying out the process, and Fig. 2 is a electrolytic effects, Whereas with continuous 0 4o horizontal section of the same. Fig. 3 illuscurrents there would be a tendency to reduce trates a modification. one of the electrodes and build up the other Referring to the drawings, A represents the by electrolytic action. Moreover, continuous wall of the furnace, and B the melting-chamcurrents usually tend to break up the chember therein. Two electrodes H and II eX- ical combinations of the baser metals in the 5 tend along the bottom of the chamber B. matte, and hence consume much of the en- These electrodes I usually construct of castergy uselessly. iron. They are provided with means for cir- The ore (indicated at D) is fed into the furculatin g water therethrough for keeping them nace through a suitable hopper E, which may cool. These means consist of openings h if, he closed tightly by a slide or cover 6 to pre- [00 50 and a convenient way to manufacture them vent the escape of the vapors of arsenic when consists in forming U-shaped pipes h and the furnace is in operation. The circuit for the electric current is completed from one electrode to the other through the mass of ore D. This ore may be any arsenical ore bearing sufficient iron or other metal to afford a conducting path for the current. An ore which affords a large supply of arsenic and which may be treated with advantage by my process,is what is known as mispickle. The resistance offered by the ore is sufficiently great to cause sufficient heat to be generated therein to melt it and to thereby liberate the arsenic, which then passes in the form of metallic vapor through the pipe or pipes E into any suitable form of condensing vesselsuch as indicated at G G, for instance. In the drawings I have shown the vessels G G as being made in compartments, so that the vapors pass downward through the compartment g and upward through the compartment g. At the base of the condensing vessels suitable openings are provided for access thereto in order to remove the arsenic, as indicated at g. The vapors passing through the condensing vessels may pass out at a pipe 9 being urged foward by a water-injector g of any suitable character, the water then passing into the vessel or tank G, where any arsenic remaining may be collected. The character and construction of the condensing vessels may be modified,as found convenient. It is usually desirable to insulate the sources of water furnished to cool the electrodes from each other, as otherwise the pipes conveying the water might afford a short circuit between the electrodes. The water may be derived, however, from a single hydrant through sections of rubber hose rror other non-conducting material. The constant circulation of water keeps the electrodes sufficiently cool,-

and thus prevents the loss of current in the electrodes, such as might otherwise result from the increased resistance offered there by when heated to a very high temperature. The melted ore freed from the arsenic may be drawn off through one or more taps O, which may be opened and closed by a plug 0, as desired.

Much of the heavy precious metals, such as gold and silver, sink downward and gather above the electrodes, and I have found it use ful in some instances to employ a layer of lead, as indicated at L L in Fig. 3, upon the surfaces of the electrodes to gather the precious metals. The electrodes are here shown as having their upper surfaces of the iron portions II II below the bottom of the chamber B. The lead will usually be in a molten state, but being of greater specific gravity than the mass of ore it will remain at the bottom of the chamber, and owing to the cooling action of the water flowing through the electrodes it will not be raised to a sufficiently-high temperature to vaporize or distil. IVithout this cooling action more or less of the lead would usually pass off into the matte. It is not essential, however, that the precious metals be collected within the furnace, as they may be carried off in the matte and afterward recovered therefrom. After the ore has been melted and the arsenic driven off, the molten iron sulfids or other material composing the matte-is drawn off through the tap O, and a new charge is placed in the furnace.

Anumber of charges may usually be treated before it is necessary to remove the precious metal from the lead in case the latter is employed; but if they are leftin the matte they can be recovered in the usual way.

For the purpose of affording convenient access to the furnaceit maybe provided with a lid M of sufficient size. The walls of the furnace may be of fire-clay or other suitable material, but the portions against which the ore rests should be composed of a non-conductor of electricity.

For the purpose of determining the current and electromotive force a suitable amperemeter A and a voltmeter V may be provid ed in a well-known manner.

The matte which is withdrawn from the f urnace being freed from arsenic may be readily and safely treated by any suitable process to recover the iron and other metals which it may contain.

I claim as my invention 1. In a furnace for treating electric conducting ores by means of electric currents, the combination of two horizontal electrodes of cast-iron, and wrought-iron pipes extended within the body of each electrode for forming a cooling-fluid circuit, said electrodes being located in depressions in the bottom of the furnace, a horizontal bed between the electrodes for receiving the ore to be treated, a vapor-escape flue in the upper portion of the furnace and a tap extending from the bed of the furnace at a point between the electrodes for withdrawing molten metal therefrom.

2. The combination of a melting-chamber, a source of electric currents, and two compound electrodes connected with said source extending along the bottom of said chamber and each consisting of a horizontal iron portion and a covering of lead, substantially as described.

3. An electrode for electric reduction-furnaces consisting of parallel superposed strata of iron and lead, the lead above and the iron portion beingperforated for the passage ofa cooling fluid therethrough.

4c. In a furnace for the reduction of ore, the combination of electrodes composed of superposed layers of iron and lead, the lead above, and means. for cooling the iron to prevent vaporization of the lead.

5. In a furnace for the reduction of ores, a bottom having a depression and a compound metallic electrode placed therein, the upper portion thereof consisting of a more-fusible metal than the under portion thereof, the upper surface being below the general surface of the bottom.

6. In a furnace for the reduction of ores, a

bottom having depressions and electrodes placed therein below the general surface of the bottom, each of said electrodes consisting of two layers of metals having different melting-points, the more fusible metal constituting the upper layer.

7. In a furnace for treating ores, the combination of a melting-chamber having the depressions (1, d*, and the electrodes H, H, located in said depressions, and having perforations h, 71 and the superposed strata of lead.

8. In a furnace for treating ores, the combination of compound electrodes comprising a normally-non-fused portion and a superposed readily-fusible portion, the chamber having depressions receiving the electrodes, the charging and discharging openings, and the removable cover.

9. In a furnace for electrically treating ores, 

